This invention relates to impulse tools, particularly tools that shut off a driving motor at a predetermined torque output.
Presently tools with torque sensitive shut-off devices either have a piston mounted on the centerline of the impulse mechanism that moves a rod on the centerline of the motor to operate a shut-off device or have a piston mounted off the centerline that moves a complex and unreliable ring shaped air valve. Both of these configurations are undesirable because they make the tool relatively long and heavy, make the valving and porting complex, and provide inadequate performance.
With this invention an impulse tool has a shut-off system that enables a lighter, simpler and more reliable tool to be manufactured. This is accomplished in part because the shut-off piston is located in the housing of the impulse mechanism where space is available, thereby eliminating the need to increase size, and because the shut-off piston motion is transferred without requiring a complex rear cover or spindle or any mechanical pivots to reduce friction problems, and because fewer seals are required.
Other advantages of this invention will be apparent from the following detailed description.